why does `watch -e` create two processes ?

[bows7ring]

Hey there!

Problem details :

I write an executable in Python, in order to get the usbguard events via watch -e interface.

However, usbguard may create two process，only when USBGUARD_IPC_SIGNAL is classified as Device type, such as Device.PresenceChanged, Device.PolicyChanged.

Here is my log :

Actually, I printed the pid of processes using C++, the result was the same.

Is this the right execution result?

I wonder why, and how to deal with it, because this issue may affect the results of my monitor program.

Any help would be appreciated! And, of course, thank you for opensourcing this excellent tool.